A leaky pressure relief valve can reduce the performance of your inflatable raft or kayak. In this instructional video, the NRS Repairs Department shows you how to inspect, clean and fix your pressure relief valve so you can get back out on the water. The Leafield A6 Pressure Relief (PR) valve prevents damage that can be caused by over-inflation in NRS and other manufacturers' inflatables. All self-bailing NRS rafts and kayaks come with an A6 PR valve in the floor. A leaky pressure relief valve is usually caused when grit or debris impedes the seal.